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Spec Mammalia: Metatheria
Marsupials are the first of the two great groups of therian (live-bearing) mammals, distinguished by their tendency to expel the embryo from the womb at a very early stage, and then nurse the infant externally while it develops. The clade in which they are part of, the metatheres, originated in the Early Cretaceous, possibly in North America, and then spread around the globe. Today, marsupials are most numerous in Australia , where almost every mammal belong to that order. They also exist in great numbers in South America and some dwell in Eurasia and North America. For the most part, Spec's metatherians are normal, diminutive Spec mammals, but this rule of thumb is not always followed. The Pliocene and Pleistocene brought with them massive environmental changes that did much to loosen the dinosaurs' hold on terrestrial niches. The Ice Age replaced the forest and jungle of the dinosaur world with tundra and steppe, driving many clades to extinction and opening opportunities to others. The oceans were also open for colonization by mammals, and the otter-like selkies and each-uisges have made full advantage of this habitat, even going so far as to push the dinosaurian hesperornithians out of many of their niches over the course of the Neogene. NESODELPHIA (Malagasy 'possums') SUCHOTHERIIDAE (Selkies and each-uisges) These primitive metatherians are otter-like, with stumpy legs and long, flexible bodies, but possess large conical teeth more similar to crocodilians than those of any mammalian group. They range across the Arctic oceans, in both freshwater and saltwater environments, eating fish and (in some species) larger game. Unlike their pinniped counterparts, however, suchotheriids lack insulating blubber, and so grow dense coats of fur to keep them alive in the frigid water that are their home. Selkies keep their fur water-repellent by producing oil from a preen gland (rather like that of a duck) and spreading it over their bodies. From their general morphology and from a few scant fossils, suchotheriids seem to derive from the very base of the metatherian family tree. Their dentition, having been adapted for the use of fish-catching, tells us little about their ancestry, but the selkies are probably derived from small, weasel-like carnivores such as Deltatheridium, which inhabited Asia during the Cretaceous. Eocene fossils show that these little carnivores were quite widespread during the Paleogene, and inhabited a wide number of niches. It was not until the Miocene, however, that we begin to find fossils that can be reliably ascribed to Suchotheriidae. As marsupials, suchotheriids cannot give birth to their young in the water, as walduks or RL cetaceans do. A mother selky comes to shore to give birth to her single, fetus-like baby, which crawls from the womb into an insulated pouch on the belly. While her baby is in this pouch, the female cannot enter the water, and so she depends upon the infant's father, who either must catch fish for her to eat, or transfer the baby into his own pouch. The portion of time spent between mother and father varies widely between selky species, although there is little physical variation in a species. The each-uisge ("ehk-whizkee") is found in cool lake environments in Great Britain and Scandinavia. Although beautifully streamlined for swimming, the each-uisge can travel considerable distances overland when looking for a new territory. Voracious carnivores, each-uisges will take a wide range of fish, crustaceans, turtles and amphibians. They will opportunistically attack small dinosaurs by the waters' edge but their lack of a reptilian metabolism prevents them from mounting lengthy croc-style ambushes. Each-uisges pair for life, the female gives birth to 3-5 semi-developed young which are nursed in a burrow or den to which the male brings food. Both partners retreat to the burrow to hibernate during winter. The animal has unusual spy-hopping habits in the water, often pricking it's ears with its head and neck raised out of the water, giving it a horse-like appearance (leading to its common name). Occasionally, it will briefly raise the upper 2/3 of it's body out of the water vertically, giving a distinctly serpentine impression. This habit is almost certainly the source of unsubstantiated but persistent reports of a late-surviving elasmosaurid dwelling in Loch Ness. Unlike their relatives,caspian seawolves(Selkis chooi) are not at all social, and in fact individuals of this highly territorial species are fully capable of killing their co-specifics in battles over hunting grounds. The only time these predators tolerate each other is during and immediately after mating, when the male and female must first conceive, and then nurture the season's litter.Seawolf child-rearing follows the same general pattern of other suchotheriids, but in a dramatically shorter time, and on a much larger scale. Seawolves time their births to coincide with seaguin and jarrk nesting, and for a single month during which eggs and nestlings offer abundant food at little metabolic cost, the seawolf pups are stuffed with calories. They mature at one of the most rapid pace of any synapsid known. From birth to their first month, the pups literally grow from the size of a plantain to nearly 1.5 meters and 30-40 kilos.As food supplies diminish, the seawolves' old territorial instincts kick in and the parents drive off both each other and their pups. At this point, the pups, of which there are often over half a dozen, can more or less fend for themselves, and after the elements and a few violent intraspecific battles have winnowed the new generation down, the territorial lines have been redrawn, seawolf affairs return to normal.caspian seawolves are actually more widespread than their name sake indicates. Populations range along the European Atlantic coast into the Mediterranean and both the Black and Caspian sea. The size range can vary greatly. The originally described Baltic populations generally reach 300 kilos. The more southerly populations rarely exceed 200 kilos. These seawolves also are quite common in the reaches of very large rivers, such as the Danube and Dnieper. They are the fatal horror of unwary dinosaurs and mammals who wander down for a drink. STAGODONTIDAE (Hoeks and baskervilles) Distant cousins of the aquatic selkies, possum-hounds are a wide-spread group of Laurasian metatherians. These nocturnal carnivores may be found throughout the Northern Hemisphere, though their greatest diversity is in North America, where they take over many niches that, on other continents, are reserved for dinosaurs. Some, like the baskerville , approach the size of RL canids. Many scholars link the possum-hounds to the stagodontids, a group of tasmanian-devil-like metatherians that produced such monsters as Didelphodon, the largest mammal known from the Mesozoic. Thus, the opossum-hounds' original name of Metacanidae has been discarded as a formal taxon, and Stagodontidae extended to include these modern species. SAMPLE TAXA: North America * Wepwawet , Seculasaurus vulgaris, and spotted jaub, Spadavis onca (north western North America)]] The baskerville (Metacanis phobos) is the largest of the possum-hounds (Metacanidae), and can be found in the cold, boreal forests of Eurasia and North America (although the larger subspecies, M. p. gigas is endemic to North America). These carnivores range in size from 15kg (the Eurasian subspecies) to more than 20, and in most respects resemble the mustelid wolverines (Gulo gulo) of Home-Earth. Baskervilles are vicious and tenacious hunters, willing to run, climb, and swim in their pursuit of prey. They are also fond of carrion, which they locate with their excellent sense of smell. The most noteworthy feature of the baskerville, a trait unique among mammals, is bioluminescence. For most of the year, baskervilles look like any other possum-hound, but during the mating season (January-March) the males develop a strip of green-glowing tissue along their spines. This skin is hidden by a mane of hair down the animal's back, and can be revealed by flexing sub-dermal muscles and spreading the mane apart. The source of the eerie greenish glow that has earned the baskervilles their name is, in fact, the fungus Rhizolucifrus baskervillensis. This mushroom, a bioluminescent rhizomorph related to the genus Armillarielia (common to both Spec and Home-Earth), probably started out as a dermal parasite, growing as an infection on the skin of a possum-hound. However, the fungus's ability to glow (which it evolved for purposes of its own) must have proven useful to the ancestral baskervilles as a mating signal. A male that glows, after all, is a male that harbors a strength-sapping infection that reveals his location to predators and prey. The very fact that such a male is alive means he must have a set of very beneficial genes, and would thus make a good father. Of course, the same infection that makes males more attractive has no beneficial attributes to females or juveniles, and so the baskervilles have evolved an immune response that inhibits the growth of the glowing mycelia. Most baskervilles do carry the fungus, but not in sufficient quantities to glow or to be of any noticeable detriment to their health. During the fall, however, the males' immunity begins to wear off. At the same time, they produce saccules of nutrient-rich fluid on the skin of their backs, which they rub against other males to spread the fungal spores. By early January, their backs are glowing brightly. The glowing males' attractiveness to females comes at a price, however. Glowing males are noticeably less energetic than females and juveniles, their strength sapped by the fungus on their backs. They can, however, decrease the flow of nutrients to their phosphorescent saccules, damping their glow and saving energy. During hunting, a male baskerville can hide some of his glow by closing his mane over the naked skin of his back. Interestingly, breeding males often hunt together (a contrast to their solitary behavior the rest of the year), and seem to be able to use their glow to communicate over distance, opening and closing their mane like a semaphore to transmit a code of glowing pulses. The European baskerville subspecies looks superficially quite different from its American cousins, but the difference is literally skin deep. The European baskervilles, nicknamed "tuonenhurtta" after the Finnish land of the dead, seem to be a partly melanistic variant of M. phobos. It is yet unknown what kind of advantage the darker pelt gives over the lighter colors, or if the darker fur is merely connected to another more clearly beneficial mutation. The bat-eared hoek (Auritobestia renititor) is a fleet-footed stagodontid completely adapted to the arid environment of Spec's southwestern North America. This small nocturnal carnivore hunts for small lizards and snakes, burrowing beetles, spiders, scorpions and other invertebrates. The bat-eared hoek has a relatively good night vision, but this is nothing compared to its acute hearing. They can hear their prey moving beneath the sand from many meters away, and are claimed to be able to sense even the hearbeats of a still-lying animal. Bat-eared hoeks are solitary animals, and when the paths of two hoeks cross, results may be rather violent. A cornered hoek can also defend itself very aggressively, and many a scientist has had the displeasure of proving the glove-pearcing sharpness of its teeth. When threatened, the hoek usually makes loud barking noises, which are said to resemble the sound of an asthmatic chihuahua. (The name "hoek" is in fact an onomatopoetic reference to the animal's bark.) the Golden homba (Alopecitherium gilvus) is the widest ranging of the stagodontids . Found throughout the Holarctic, these adaptable possum-hounds were the first to be collected. Their coloring and small size not withstanding; the remarkable convergence onto HE foxes lead to the Richard Adams honorific for the group as a whole. Offspring are conceived in late winter, with 2-6 young crawling into the backward facing pouch. They remain there for three months, carried by their mother until weaning. During the latter part of the in pouch stage, the mother will forcefully expel her young to feed on caught prey and found fruiting patches. The weaning period results in permanent expulsion,with the young kits following their mothers for an additional month before both mother and father drive them out of the local territory. Golden hombas are quite flexible in food requirements as reflects their omnivorous nature. This coupled with their secretive natures has allowed them to spread from their North American homeland throughout the temperate and boreal forests of Eurasia. Golden hombas have even been seen far out on the Arctotitan Steppes, usually in close proximity to gallery and esker forests. Though as we'll see, they have not been successful in settling the temperate regions of North America. There, they are limited to the taiga and western alpine regions. The alpine golden hombas are distinct in having a very light white gold coat. DIDELPHIDAE (Opossums) Many New World marsupials belong to the large and varied family Didelphidae, which on Home-Earth is represented by opossums. These marsupials are distinguished by the fact that they give partial birth to an embryo from one womb into another, where it develops for a time before graduating to a pouch. Didelphids are very similar to the marsupial precursors, and most have retained the ancient habits of the arboreal insectivore. The sugar cat (Shofixti reichefordi) is a dweller of the rainforest canopy. Though it looks like a cross between a cat and a squirrel, it is a metatherian not unlike HE possums. The sugar cats were originally thought to be exclusive frugivores, but close observation has proven them to be opportunistic omnivores that will even occasionally raid arbronychosaur nests. Naturally these arboreal dinosaurs are also compete with the sugar cats for food, but the secret of the metatherians' success seems to be their prehensile tail that functions effectively as a fifth limb. The sugar cats are monogamous and live in tightly knit pairs that rarely leave each others's sight. The males are known for their downright suicidal attacks against any threat against the litter they've sired. If a sugar cat feels its nest is being threatened, it may go completely berserk and fearlessly attack an invader as large as a human being. Since the sugar cats have large curved claws and cutting incisors they can do a lot of damage even if they perish in their desperate act of defense. POLYDOLOPOIDIDAE (Stimpies and teddies) Thylacoursinae Thylacoursines, called variously "teddies", "spec-bears", and "non-koalas", are placid, heavily-built didelphids that evolved in North America during the Miocene and invaded South America during the Great Interchange of the Pliocene. Most thylacoursines are omnivorous or herbivorous, but one genus Thylacoursus ''is actively predatory. The "drop-bear", if it exists, is probably a member of this genus. Stimpies and teddies are placid, heavily-built arboreal metatherians somewhat related to the didelphids. They evolved in South America, and the vegetarian, koala-like stimpies are found only in that continent's jungles, but the more omnivorous teddies extend far into North America. Though deceitfully similar to koalas in appearance, stimpies (genera ''Thylacoursoide''s and ''Vestiursa) are only distantly related to the Australian marsupials. The large hairless noses of stimpies are used by the marsupials to tell different species from each other as well as sexual ornaments and resonance chambers to amplify the stimpies' calls. The existence of such an organ has lead many biologists to question the old view of stimpies as solitary animals. The smaller, somewhat more nimble teddies (genus Thylacoursus) extend throughout South America and most of North America , although they vary little with distance. Most are small, no larger than 2 kg, but there have been several reliable reports of a much larger Thylacoursus species in the deciduous forests of western North America SAMPLE TAXA: South America * Bluenose stimpy * Spectacled stimpy * Kilted stimpy Category:Atlantic Ocean Category:Spec Dinosauria Category:Mammals Category:Alternative timelines Category:Alternative evolution Category:Alternate History Animals Category:South America Category:Asia Category:Therapsids Category:Synapsids Category:Cynodonts Category:Neotherapsids Category:Theria Category:Metatheres Category:Amniotes Category:Craniates Category:Herbivores Category:Omnivores Category:Madagascar Category:Europe Category:North America Category:Arctic Category:Carnivores Category:Australia Category:New Guinea Category:Aquatic Creatures Category:Pacific Ocean Category:Marsupials